Question 2061
For a geometric sequence with given a1 and r, we have

 a(n) = a(1)* r^(n-1),

 So,when n = 6, a(6) = a(1)* r^5 = 5*37^5 = 346719785.

 For arithemic series with given a1 and d, we have

 a(n) = a(1) + (n-1) d
 When n = 7, a(1) = 3,d =2, a(7) = 3 + 6 * 2 = 15.


 It seems you have to remember these basic formulas.

 Kenny